Psychosocial Dimensions of Learning Disability Subtypes: Neuropsychological Studies in the Windsor Laboratory

Psychosocial Dimensions of Learning Disability Subtypes

Evidence bearing upon the relationships between profiles of neuropsychological assets and deficits, subtypes of learning disabilities, and patterns and degrees of psychosocial functioning is reviewed. The dimensions of incidence and type of psychosocial disturbance and the differential manifestations of these in two subtypes of learning disabilities are examined. Conclusions relating to the neurodevelopmental bases of the pattern of psychosocial functioning most often seen in children and adolescents with the syndrome of nonverbal learning disabilities are emphasized.

Nonverbal learning disability

Nonverbal learning disability (NLD) is described as a subtype of specific learning disability where the source of the disability is a difficulty in processing nonverbal information. The child with NLD presents with problems in visual, spatial, and tactile perception but with strengths in rote verbal skills. Traditionally, these children were recognized by their difficulties in arithmetic which presented a stark contrast with their strengths in spelling and decoding text. They also exhibited a split between their verbal IQ (VIQ) and performance IQ (PIQ) scores with the VIQ being significantly higher than PIQ. Over time, however, diagnostic criteria have evolved and the broadened definition of the NLD syndrome has led many to question the utility and uniqueness of the NLD diagnosis. In addition, shifting diagnostic standards have made research results difficult to replicate. In short, the research to date leaves many unanswered questions about (1) the definition of the NLD syndrome, (2) the pervasiveness of the academic, social and psychopathological difficulties, (3) the source of the NLD syndrome, and (4) the degree to which it overlaps with other conditions. This chapter outlines a brief history of the NLD syndrome, how it is currently conceptualized, and some of the current debate about the unanswered questions above.

What's new in autism?

This review on autism spectrum disorder (ASD) focusses on recent insights in the clinical picture, such as continuity of the phenotype and the concept of broader phenotype, on epidemiology and on clinical issues relevant to physicians, including new methods for early screening and diagnosis, psychiatric and somatic co-morbidity, and the expansion of so-called complementary and alternative treatments. ASD is a disorder with mainly genetic causes and recent insights show that a variety of genetic mechanisms may be involved, i.e. single gene disorders, copy number variations and polygenic mechanisms. Technological advances in genetics have lead to a number of promising findings, which, together with other lines of fundamental research, suggest that ASD may be a disorder of connectivity in the brain, at least in a subgroup of patients. It is possible that part of the genetic load in autism actually reflects gene-environment interaction, but there is no evidence for purely environmental causes in a substantial number of cases. Clinical research suggests that ASD may be a multi-system disorder in at least a subgroup of subjects, affecting the gastro-intestinal (GI) tract, the immune system and perhaps other systems. Behavioural treatments remain the cornerstone of management, and are mainly aimed at stimulation of the domains of impaired development and reducing secondary behaviours. These treatments are constantly being refined, but the main progress in this area may be the increase of research on effectiveness.

Behavioral Problems and the Effects of Early Intervention on Eight-Year-Old Children with Learning Disabilities

OBJECTIVES

1) To investigate the comorbidity of verbal and nonverbal learning disability subtypes with several domains of behavior problems among 8-year-old children. 2) To determine whether receipt of an early intervention modified the association between childhood behavior problems and learning disabilities (LD).

METHODS

This is a secondary data analysis of the Infant Health and Development Program (IHDP), a randomized clinical trial of an early intervention provided between ages 0 and 3 involving 985 children born low birthweight and premature. The findings are based on a prospective follow-up of these children at 8 years of age.

RESULTS

Compared to children without verbal LD (VLD), those with VLD were twice as likely to exhibit clinical levels of total behavior problems and 89% more likely to exhibit externalizing behavior problems. Analysis of specific subscales of behavior revealed significant associations with anxious/depressed and withdrawn behaviors, as well as an increased likelihood of attention problems among children with VLD. No significant association was found between nonverbal LD (NVLD) and any type of behavior problem. Furthermore, there was a significant interaction between VLD and the intervention, in which the odds of internalizing behavior problems were greater among children with VLD. No interaction effect of the intervention occurred for any type of behavior problem among children with NVLD.

CONCLUSIONS

These findings provide evidence that distinct differences exist for different learning disability subtypes with regards to behavioral outcomes and the effects of early intervention services among 8-year-old children.

Emotional adjustment and school functioning of young adolescents with multiple versus single learning disabilities

Early adolescents (Grades 6-8) with multiple learning disabilities (LD; reading and math) in inclusive settings were compared to adolescents with single LD (reading or math) and typically achieving (TA) peers regarding their psychosocial functioning in two areas of adolescent well-being: emotional adjustment and school functioning. The Behavior Assessment System for Children (Reynolds & Kamphaus, 1998) Self-Report of Personality for adolescents was used to determine well-being. One hundred twenty middle school students-15 boys and 15 girls in each group-were included in the current study. The results confirmed that adolescents with multiple LD (reading and math) reported poorer functioning (i.e., higher T scores) on school maladjustment, clinical maladjustment, emotional symptoms index, attitude to school, atypicality, and depression when compared to TA peers but not when compared to peers with a single LD (reading or math). All three groups differed from the TA group (but not from each other) on sense of inadequacy, with the multiple LD group reporting the highest T scores. Additional analyses indicated significant differences between girls and boys, regardless of disability status. Girls reported higher T scores on the emotional symptoms index, social stress, and depression, but boys reported greater school maladjustment and sensation seeking. Implications for practice and recommendations for future research are discussed.

Nonverbal learning disability: a tutorial for speech-language pathologists

Nonverbal learning disability (NLD) is a diagnostic category that is unfamiliar to most speech-language pathologists. This brief tutorial describes NLD's characteristics, a theoretical model proposed to explain its source, and areas of overlap between NLD and similar diagnostic categories. The communicative profile, made up of difficulties in pragmatic and semantic language in the presence of relatively preserved syntactic skill, is also discussed. Empirical evidence relevant to NLD is also evaluated. Many questions remain unresolved, but until systematic research provides definitive answers, speech-language pathologists are encouraged to rely on careful description of the individual child's communicative strengths and weaknesses to identify appropriate targets and to focus intervention on improving the child's ability to communicate effectively in everyday contexts.

Evaluating the relation between memory and intelligence in children with learning disabilities

Although both intelligence tests and memory tests are commonly used in neuropsychological examinations, the relationship between memory and intelligence has not been fully explored, particularly for children having learning disabilities. Memory, or the ability to retain information, was evaluated using the Test of Memory and Learning, a recently released test that gives a comprehensive measure of global memory functioning. This, and the Wechsler Intelligence Scale for Children-Third Edition, used to assess intelligence, were given to 80 students with learning disabilities. The correlation between a global measure of memory and a global measure f intelligence was significant (r = .59), indicating that memory should be viewed as an important component when evaluating children with learning disabilities.

Spatial and emotional aspects of language inferencing in nonverbal learning disabilities

Although subtle linguistic deficits have been postulated for children identified with nonverbal learning disabilities (NLD), there is little empirical evidence to support this contention. Two experimental language inferencing measures that have been demonstrated to be problematic for individuals with right hemisphere brain damage (RHBD) and one norm-referenced inferencing task were examined in three groups of children aged 9-13: (1) children with NLD (n = 14), (2) children with verbal impairments (VI) (n = 14), and (3) children without learning disabilities who served as controls (n = 19). The NLD and VI groups did not differ from one another on any of the three measures, indicating a generalized language inferencing deficit in the NLD group. Relative to the control group, however, the NLD group experienced specific difficulties with spatial and emotional inferencing. The implications for right hemisphere involvement in the NLD profile are examined in relation to the effects of working memory on inferential abilities.

Right hemisphere, white-matter learning disabilities associated with depression in an adolescent and young adult psychiatric population

Four hundred and eighty-four adolescents and young adults at an inpatient psychiatric facility were diagnosed as nonverbal learning disabled, verbal learning disabled, general learning disabled, or normal psychiatric controls. The nonverbal learning disabled group had the highest incidence of depression and was clearly different from the reading disabled group (66.3% vs. 33.3%). Nondisabled subjects were significantly more likely than the other subjects to be diagnosed with adjustment problems. Depressed subjects were significantly younger and more likely to be female. This study supports the contention that right-hemisphere, white-matter, arithmetic-disabled adolescents and young adults in a psychiatric population are at greater risk for depression than are psychiatric patients not showing this pattern.

Psychosocial dimensions of learning disabilities: external validation and relationship with age and academic functioning

This study was designed to assess the following in a group of 152 children with learning disabilities between the ages of 7 and 13 years: (a) the relationships between age and psychosocial functioning: (b) the relationships among psychosocial functioning, cognitive abilities, and academic achievement; and (c) the external validity of statistically derived psychosocial subtypes. Participants were assigned to one of seven psychosocial subtypes on the basis of a profile-matching algorithm. Overall, the findings suggested no increase in psychopathology with advancing age. In addition, clear relationships were found between academic achievement patterns and personality subtypes. Finally, the subtypes could be distinguished on the basis of a behavior problem checklist not used for the construction of the subtypes.

Wechsler IQ profiles in diagnosis of high-functioning autism

A Wechsler Intelligence Scale profile characterized by VIQ < PIQ with lowest subtest score on Comprehension and highest on Block Design has been associated with autism. Recently, this profile has been applied to assess the accuracy of diagnosis in research samples and for differentiating autism from similar disorders in high-functioning individuals. Universality of this profile, however, has not been sufficiently demonstrated. We therefore examined WISC-R and WAIS-R profile characteristics in 81 rigorously diagnosed high-functioning (VIQ and FSIQ > 70) children (n = 45) and adults (n = 36) with autism. Analysis of the profiles in these groups did not reveal the presumed typical VIQ < PIQ pattern. The typical subtest pattern was found, but the magnitude of profile variability was small. We concluded that individuals with autism can demonstrate a wide range of ability levels and patterns on the Wechsler scales, without a single characteristic prototype. Use of IQ score profiles in the diagnosis and differential diagnosis of autism in high-functioning individuals is not considered valid.

Evidence of nonverbal learning disability among learning disabled boys with sensory integrative dysfunction

The presumed sensorimotor basis of the nonverbal learning disability syndrome was investigated among 90 learning disabled boys (M age = 6 yr., 8 mo., SD = 12.2 mo.) with sensory integrative dysfunction. The majority of the boys were Caucasian, lower to middle socioeconomic status, and from urban, English-speaking families. 14% (n = 13) of the boys satisfied core discrepancy criteria for nonverbal learning disability, including both a significantly higher Wechsler Verbal than Performance IQ and a higher standard score in Reading than Arithmetic on the Wide Range Achievement Test. Compared with a control group of 19 boys from the same sample who had no significant discrepancies, boys with nonverbal learning disability had significantly greater weaknesses in space visualization and visuomotor coordination. As predicted, rote verbal memory and syntactical strengths were also exhibited by boys with nonverbal learning disability, but the two groups did not differ significantly.

Absence of ear advantage on the consonant-vowel dichotic listening test in adolescent and adult dyslexics: specific auditory-phonetic dysfunction

The present study investigated auditory-phonetic processing in a group of adolescent and adult reading disabled subjects. Right- and left-handed dyslexic subjects were compared with an age, sex, and handedness matched control group. All subjects were studied with a consonant-vowel version of the dichotic listening task with repeated presentations of dichotically presented pairs of CV-syllables. Left and right ear correct scores were compared for ear advantage in each of the different subgroups of subjects. The main finding was the absence of an expected right-ear advantage (REA) in the right-handed dyslexic group as compared to the right-handed normal readers. Both the dyslexic and normal left-handed groups did not show a REA. The findings are discussed within a theoretical framework that focuses on a basic auditory-phonetic processing dysfunction in developmental dyslexia that persists into adulthood.

Academic achievement in high functioning autistic individuals

Academic achievement levels in 54 high functioning (IQ > 70) autistic subjects were compared with those of 41 normal controls, who did not differ significantly in age, IQ, gender, race, or SES from the autistic subjects. The measures of academic achievement used included portions of the Detroit Tests of Learning Aptitude-2, the Woodcock Reading Mastery Test, and the Kaufman Test of Educational Achievement. Based on prior neuropsychological findings, it was hypothesized that autistic subjects would not differ from controls on subtests assessing mechanical and procedural skills, but would differ on subtests measuring comprehension and interpretive skills. As predicted, the autistic subjects performed significantly less well than controls on comprehension tasks, but not on mechanical reading, spelling, and computational tasks. This pattern is at variance with the typical academic profile of individuals with disabilities in reading or spelling, but shares some features with the nonverbal learning disabilities.

Principal identifying features of the syndrome of nonverbal learning disabilities in children

The identifying features of the syndrome of nonverbal learning disabilities (NLD) were examined with a view to determining their relative discriminant validity. A stepwise linear discriminant function analysis of children with NLD (n = 29), children with reading and spelling disabilities (Group R-S; n = 27), and a group of nonclinical children (NC; n = 27) on 15 neuropsychological variables yielded a subset of scores on four tests (Target Test; Trail Making Test, Part B; Tactual Performance Test; and Grooved Pegboard Test) that accurately (> 95%) discriminated the NLD group from the R-S and NC subjects. Of the neuropsychological features of NLD described by Rourke (1987, 1988b, 1989), deficits in visual-perceptual-organizational psychomotor coordination and complex tactile-perceptual skills appeared to be most representative (in the sense of most discriminative) of the NDL syndrome in the children examined. These are also the dimensions that are considered to be "primary" in the NLD model (Rourke, 1989). Replication of these results, employing children with other clinical disorders, is necessary.